ATPR induces acute promyelocytic leukemia cells differentiation and growth arrest by blockade of SHP2/Rho/ROCK1 pathway

Targeting SDCBP2 in acute myeloid leukemia

Acute myeloid leukemia (AML) remains a biologically heterogeneous disease with high morbidity and mortality under the existing treatment strategies. Our previous study showed that E2A might be a potential therapeutic target for AML, but the underlying mechanism was unclear. Here, we found that SDCBP2 might be a target gene of E2A through RNA-seq combined ChIP-seq screening. This was also demonstrated by Co-IP experiment. Furthermore, the expression of E2A and SDCBP2 were increased in both AML cell lines and patient samples. Downregulation of SDCBP2 expression suppressed proliferation and induced differentiation of AML cells. In human xenograft mouse leukemia model, inhibiton of SDCBP2 expression delayed AML progression. Overall, the above results confirmed that SDCBP2 might be a target gene of E2A and a potential therapeutic target for AML.

A novel all-trans retinoic acid derivative regulates cell cycle and differentiation of myelodysplastic syndrome cells by USO1

4-Amino-2-Trifluoromethyl-Phenyl Retinate (ATPR), a novel all-trans retinoic acid (ATRA) derivative, has been demonstrated that it had a variety of anti-tumor effects by exerting regulation on cellular proliferation, apoptosis and differentiation. Here, we found that ATPR is critical for alleviating myelodysplastic syndrome (MDS) and acute myelogenous leukemia. USO1, vesicle transport factor, belongs to tether protein family and involved in endoplasmic reticulum to Golgi trafficking of protein which is important to tumorigenesis. How USO1 contribute to MDS remain elusive. USO1 is aberrantly activated in MDS and AML in vivo and vitro, aberration of which might be a dominant mechanism for MDS cell survival. During the ATPR-induced remission of MDS, in vitro, USO1 presents a time and concentration-dependent decrease. Silencing of USO1 promotes myeloid differentiation of MDS cells and inhibits MDS cellular proliferation while USO1 over-expression has the opposite effect, suggesting that reduction of USO1 enhances the sensitivity of SKM-1 cells to ATPR treatment. Mechanistically, USO1 exerts its oncogenic role by inactivating Raf/ERK signaling, while ATPR is access to revise it. Notably, the activity of Raf/ERK pathway is required for the development and maintenance of MDS cell proliferation. Collectively, our results demonstrate the USO1- Raf/ERK signaling axis in MDS and highlight the negative role of USO1 in ATPR-regulated remission of MDS.